n*x dudes: Even though I deal with Microsoft Exchange (unlike everyone here, I guess), I'm hoping that you might help me figure out the best way to reject "bad" mail -- NDR or 550-5.5.1?
Issuing a "non-delivery report" (NDR) for each undeliverable mail received costs me bandwidth, CPU load, and disk space. Exchange wants to do this by default, unlike Sendmail. A 550-5.5.1, as I understand, (e.g. blogs.msdn.com/dlemson/archive/2003/10/17/52019.aspx), tells the sending MTA to bounce the reply to the sender of the email, rather than having me bounced it back. This saves a huge load on my mail queue. I am bombarded by spammers (one user alone got like 4000 emails in his inbox when I rebuilt an Exchange server this weekend) and am looking for some good ways to deal with this load. Roger
